Background Art
Present day approaches to spacecraft design are often single-focused on the goal of achieving compliance with technical parameters governing mission performance, such as the power required by the spacecraft, its mass or volume of payload. This single-minded design approach often produces spacecraft which are unique for each new program or application, and which have little or no components or subassemblies in common with one another. Thus, since each spacecraft must essentially be designed as a unique vehicle, the design-to-market cycle time of producing a spacecraft is quite long. Presently, a spacecraft designed for a specific application may take as long as 36-40 months or more to design, construct and test before the spacecraft is ready to be launched. These drawbacks lead to significant non-recurring labor costs, lengthy production cycle time, increased scrap materials, and repeated redesign of various subsystems of the spacecraft.
Another significant drawback with many present day spacecraft designs is the lack of serviceability. For example, the various subsystems of the spacecraft are often interconnected by a highly complex plurality of electrical, mechanical, fluid carrying and thermal elements. These elements are routed in a complex arrangement to the various components of the spacecraft and are typically not capable of being quickly and easily disconnected, should one or more subsystems of the spacecraft need to be accessed for service and/or testing. Disassembly and uncoupling of one major subsystem often requires extensive disassembly of cabling, mechanical coupling elements, fluid transfer lines and thermal elements, many of which are not capable of being quickly separated from their associated components. Often, fluid lines need to be physically cut and then re-welded or re-brazed, and then pressure tested, during re-assembly. Thus, uncoupling and reassembly of even one major subsystem often takes several days, or even weeks, to complete.
With present day spacecraft, the organization of its various subsystems are further not arranged in logical, fully functional, modular sub-component form to facilitate access to, service and testing of functionally related sub-components. This further contributes to extremely time consuming disassembly procedures being required before access can be gained to the specific subsystems of the spacecraft being serviced or tested. Often, a significant number of other unrelated subassemblies of the spacecraft may need to be removed before being able to access and test the desired subassembly/component. These drawbacks with present day spacecraft designs contribute significantly to their lengthy design-to-market cycle times.
As will be appreciated, the inability to quickly and easily access and/or uncouple and physically remove a particular subsystem of the spacecraft introduces significant additional cost, in terms of labor, into the overall cost of manufacturing the spacecraft. This is in large part because of the significant testing that must be performed on the numerous components of the spacecraft before the spacecraft is ready for launch. It also can cause significant time delays which could jeopardize delaying a planned launch of the spacecraft if a portion of the spacecraft has to be disassembled, re-tested and then reassembled shortly before a scheduled launch.
Since most present day spacecraft are designed with the goal of meeting particular customer requirements, often the subassemblies of the spacecraft are not usable in subsequent spacecraft, thus requiring new design efforts when designing and manufacturing a subsequent spacecraft to different customer specifications. This also contributes significantly to the high cost of present day spacecraft and the long design-to-market cycle times needed to produce such spacecraft. The re-designing of the various subassemblies of the spacecraft also prevents the cost savings that would otherwise come with the manufacture of standardized modules or subassemblies which could be used on more than one spacecraft.
Still another disadvantage of the present day spacecraft design is the inability to easily integrate improvements into various subsystems or subassemblies of the spacecraft without requiring re-design of other subsystems. Thus, if one spacecraft required a more powerful propulsion system, it would be much more cost effective and require much less design time if merely the propulsion system of the spacecraft could be re-designed and then either re-introduced into the same spacecraft or used in a different spacecraft without interfering with the design or operation of other subsystems, and without requiring disassembly of a major portion of the spacecraft.
It is therefore a principal object of the present invention to provide a spacecraft comprised of a plurality of functionally independent major modules which may be independently accessed and/or removed from the spacecraft without requiring significant and time consuming disassembly of numerous electrical, mechanical, fluid carrying and thermal interconnecting components securing the affected module to other modules of the spacecraft. In this manner specific modules may be accessed, serviced and tested without requiring significant additional disassembly of other modules of the spacecraft. This would significantly reduce the man hours required for testing and servicing the various modules of the spacecraft as well as the cost associated with such procedures.
It is another object of the present invention to provide a spacecraft having a highly modular design such that the various modules thereof may be used in various derivative and future spacecraft applications.
It is still another object of the present invention to provide a spacecraft comprised of a plurality of functionally independent modules each having its electrical, mechanical, fluid carrying and thermal interconnecting elements configured such that each module may be selectively moved, relative to one another, to enable access to portions of the spacecraft which would otherwise only be accessible through hours, or possibly days or weeks, of time consuming disassembly efforts.
It is yet another object of the present invention to provide a method of manufacturing a spacecraft which involves using functionally independent modules that are secured to one another via fastener assemblies including quick disconnect fasteners and conventional electrical connectors, to thereby enable parallel manufacturing, design, testing and/or removal of selected modular subsystems, to thus significantly reduce the overall time required to construct, test and service the various major functional subsystems of the spacecraft.